A number of fenestration units, such as windows, have one or more movable sashes. Some windows, known as single hung windows, have one movable sash and one stationary sash. Some windows, known as double hung windows, have two movable sashes. A first sash can generally be considered as being a lower sash while a second sash can generally be considered as being an upper sash. The lower sash and the upper sash can be movable relative to each other.
In some instances, an individual may want to raise or lower one sash, such as the lower sash, without moving the upper sash. However, in some cases movement of the lower sash can cause the upper sash to move downward.